I have the buffer on the highest setting actually and it's better than when I decrease it. It's definitely a problem with cubase. I really don't know how strong my CPU is. Here are the specs of my computer
State Drive Corsair XMS3 4GB DDR3-1600 (PC-12800) CL9 Dual Channel Desktop Memory Kit (TWO 2GB Memory Modules), Danger Den 4101 Water Cooling Kit, VisionTek Radeon HD 4870 GDDR5 512MB, Gigabyte GA-P55A-UD3 ATX MotherBoard, Sony AD-7260S 24X*
SATA Internal DVD Burner, OCZ Technology ModXStream Pro 500 Watt ATX EPS12V Modular Power Supply, Sabrent 75-in-1 7-Slot USB 2.0 Internal Memory Card Reader & Writer, Core i7 860 2.8GHz Socket 1156 Processor (Over Clocked To 3.8Ghz), WITH WINDOWS*